Kant's ethics are of a sort called deontological, or based on an absolute notion of duty. To discover whether an act is morally good, one should ask whether it was done from a sense of duty alone. Thus intention is part of moral action. Immanuel Kant also believed that free will, or moral agency, was a precondition of moral action.

He had several tests for moral maxims. First, they must be universalizable. Second, they must treat all intelligent beings as ends in themselves rather than as means to an end. Finally, they must be willed as moral acts.